Articles for temporary insertion in human or animal body cavities, such as catheters and drainage systems, involve a considerable risk of infections. U.S. Pat. No. 5,295,979 (DeLaurentis et al.) states that about 40 percent of patients using urinary catheters develop urinary tract infections in the United States. About 3.2 percent of the total number develop bacteriaemia (bacteria in the blood). In the United States ten to twenty thousand people die each year, and about one billion dollars are expended to manage the complications arising from the use of urinary catheters and drainage systems. Clearly, any means which helps to reduce such infections may have a significant effect on the overall cost of medical services. Furthermore, a lot of pain, suffering, and malaise could be avoided if such infections were combated.
To this end the above U.S. Pat. No. 5,295,979 (DeLaurentis et al.) proposes a urinary catheter with a drain lumen which is coated with oligodynamic metal such as silver and arranged with a coating of a more noble metal such as platinum for creating an iontophoretic galvanic couple, which drives antimicrobial ions into solution. The exterior of the catheter is also coated in a similar manner to inhibit microbes migrating toward the bladder along the outer surface of the catheter.
The use of a noble metal such as platinum for a coating on a catheter or another article to be inserted in a body cavity is per se an expensive solution of the above discussed problem. A large number of such articles to be inserted in the body are disposable articles to be used only once which emphasises the need for a less expensive solution.
It has now been found that an alternative arrangement to the above mentioned arrangement of a metal able to form antimicrobial ions such as silver and a more noble metal such as platinum for creating a galvanic couple, which drives antimicrobial ions into solution can be obtained by the substitution of the noble metal with certain conductive non-metallic materials.
WO 2004/045577 (Møller et al.) discloses a biologically inhibiting material having a surface with separated areas of anode material and cathode material. Both the anode material and the cathode material have a positive galvanic potential, and the potential of the cathode material is higher than the potential of the anode material. The distance between any point on the active surface and the adjacent cathode material and the adjacent anode material does not exceed 200 μm. This material is useable as a construction material in equipments for food preparations or in water systems and is able to inhibit microorganisms by a galvanic process without release of significant amounts of Ag+-ions to a contacting liquid (electrolyte). This special galvanic process is not possible if the contacting liquid contains compounds able form complexes with the Ag+-ions as the case is with body fluids. Thus the biologically inhibiting material disclosed in WO 2004/045577 (Møller et al.) is not intended for use inserted in a human or animal body cavity.
Further to U.S. Pat. No. 5,295,979 (DeLaurentis et al.) examples of articles suitable for insertion in body cavities are also disclosed in U.S. Pat. No. 6,287,484 (Hausslein et al.), GB 2,287,473 (Franks) and WO 98/31420 (Elliott et al.).
WO 99/46780 (Milder et al.) discloses a silver ion releasing material having a plurality of carbon granules and a plurality of silver granules each distributed in an electrically conducting base material. Being distributed separated in the base material the carbon and silver granules are not in direct contact with each other. This arrangement gives not a satisfactory release of the silver ions due to an insufficient electrical contact between the silver anode material and the graphite cathode material.
It has now been found that an alternative arrangement to the above mentioned arrangement disclosed in U.S. Pat. No. 5,295,979 (DeLaurentis et al.) based on a metal able to form antimicrobial ions such as silver and a more noble metal such as platinum for creating a galvanic couple, which drives antimicrobial ions into solution can be obtained by the substitution of the noble metal with certain non-metallic materials.